Dear colleagues:

 I am having a problem with making SiN membranes. When I pattern the backside of
the
wafer the SiN coating on the front side gets all scratched up due to the
chucking and

handling used in our photo lithography process. These scrathes then cause our
membranes
to shatter when the SiN layer is exposed after the silicon is all etched away. I
have
tried to place a thick oxide layer (2 microns) over the SiN to protect it during
the
back side patterning. But still many defects appear. Is there any kind of
chucking machine

that protects the side which is being handled?


Thanks in advance for you help,


Jared Lera
Semiconductor R&D
Samsung Electronics